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ST. LOUIS, Missouri (CNN) — The man paces back and forth on a St. Louis street, yelling “Shoot me,” as two armed police officers approach him.

Less than 20 seconds after their arrival, the officers open fire, killing him.

As new cell phone video emerged Wednesday of the fatal confrontation that claimed the life of the African-American man, St. Louis Police Chief Sam Dotson tried to explain the officers’ action in an appearance on CNN.

Watch the cell phone video above.

The incident took place Tuesday, less than four miles away from the suburb of Ferguson where, just days earlier, a police officer shot and killed Michael Brown, an unarmed black teen — and touched off violent protests.

Dotson said the man was suspected of walking out of a convenience store with two energy drinks and a package of pastries that he didn’t pay for.

Police said the man had a knife that he pulled out, although that is unclear from the video.

“An edge weapon, a knife, within 21 feet is a lethal weapon,” Dotson told CNN. ” The officer just did, what I think you or I would do — they protected their life in that situation.”

‘Drop the knife’

The video is graphic. CNN has chosen to freeze the footage right before the man is shot, but the audio continues.

The man, dressed in khaki pants and a blue sweatshirt, is standing on the side of a street when a police car pulls up on the sidewalk near him.

He takes a few steps back as officers get out of the police cruiser and approach him, armed with guns.

They yell at the man, repeatedly ordering him to get his hand out of his pocket.